Title

Author

Date of Award

6-9-2015

Document Type

Thesis and Dissertation

Degree Name

Master of Science (MS)

Department

Department of Chemistry

First Advisor

Marjorie A. Jones

Abstract

The agricultural waste products created by industries, such as the Tequila manufacturing industry, create thousands of tons of waste material every year. This agricultural waste often becomes an environmental and ecological problem for fields and surrounding areas. The purpose of this study is to determine the potential of using the yeast Kluyveromyces marxianus 7-1 and Kluyveromyces marxianus 8-1 to ferment the leaf waste from the harvesting of the Agave tequilana as a form of bioremediation. Fermentations (anaerobic, under constant shaking, and at room temperature) were monitored for colony forming units, pH of fermentation broth, concentration of reducing sugars, and protein concentration as a function of fermentation time. Yeast products formed during the fermentation such as enzymes (inulinases), protein, and the yeast cells are considered important due to their current market value and use as feedstock for other

fermentations with Yarrowia lipolytica, Saccharomyces cerevisiae, and Rhodotrula glutinis (not the focus of this study). Endogenous compounds in the Agave tequilana leaves are also of interest to these studies such as potential natural ultraviolet absorbing compounds (mycosporine-like-amino acids).

It was determined that both Kluyveromyces marxianus 7-1 and Kluyveromyces marxianus 8-1 are able to grow on the leaves of the Agave tequilana with similar growth curves, as determined by colony forming units. Kluyveromyces marxianus 7-1 experienced a shorter lag time making it the "better" choice for an industrial application. It was demonstrated that the protein and reducing sugar concentrations have an inverse relationship with colony forming units as a function of fermentation time. Several interesting ultra violet absorbing compounds were extracted from the leaves of the Agave tequilana and a positive control (seaweed). These compounds were characterized by thin layer chromatography, UV-Vis spectrophotometry, and high performance liquid chromatography with a diode array detector. These studies demonstrate that the leaves of the Agave tequilana, which are currently considered waste, have potential to produce economically valuable products through mycosporine-like-amino acid extractions and fermentation with Kluyveromyces marxianus 7-1 and Kluyveromyces marxianus 8-1.